1. Field of the Invention
The invention relates to improvements in safety belt devices, and, more particularly, to self-retracting safety belt retractors for use on vehicles or the like.
2. Description of the Prior Art
Safety belt retractors of the type disclosed herein have been developed over the years for use in aircraft, automobiles, and similar vehicles or the like. These retractors generally combine a frame or casing having a spindle-supported reel thereon with a belt or strap automatically wound thereon and unwound therefrom in response to movement of the user. Such reels normally include a rewind to wind the belt or strap back onto the reel and cooperating locking means acting to lock the reel against rotation in case the strap, and hence the user, moves with respect to his seat at an excessive and dangerous acceleration.
However, it is desirable on such retractors to make the reel "free spooling", i.e., the belt or strap mounting reel cannot accidentally lock up due to excessive acceleration of the strap during an initial protraction thereof by the user prior to buckling the safety belt into a condition of normal use, the reel thereafter locking upon a predetermined strap or belt acceleration. Certain prior art safety belt retractors that attempted to accomplish this normally have provided for only limited "free spooling" during only a given number of initial unwinding turns of the reel on protraction of the strap. Other prior art retratractors have provided unlocking discs frictionally driven by the reel and acting directly on the locking bar to hold it unlocked during protraction. The former have the disadvantage of possible premature locking while the latter have introduced an undesirable friction drag during pulling out of the strap.